Reinforced sods have long been known in the art. Sod mats of groundcovers, flowers, and playing field grasses are among the examples.
Molnar (U.S. Pat. No. 5,346,514) discloses flower and groundcover sod mats reinforced with nylon sod reinforcements. Freed (U.S. Pat. No. 5,326,192) discloses turf surfaces reinforced with discrete fibrous material. Egan (U.S. Pat. No. 5,301,466) discloses playing field sod mats with carefully adjusted sand contents. Anton (U.S. Pat. No. 5,224,292) discloses a plant-growing nonwoven mat comprising a layer of hollow organic fibers having therein water soluble plant adjuvants. Clark (U.S. Pat. No. 5,189,833) discloses reinforced grass sod mats. Decker (U.S. Pat. No. 5,177,898) discloses a novel method to grow sod. Malmgren (U.S. Pat. No. 5,020,936) discloses an animal running surface having shredded rubber therein. Malmgren (U.S. Pat. No. 5,014,462) discloses soil amendment of turf with rubber particles. Moffet (U.S. Pat. No. 4,959,926) discloses a plant growth medium having small tufts of mineral wool fibers. Decker (U.S. Pat. No. 4,986,026) discloses tall fescue sod mats which are very large and employ planting mediums containing straw and sewage sludge. Milstein (U.S. Pat. No. 4,941,282) discloses wildflower sod mats reinforced with polyester fabrics. Walton (U.S. Pat. No. 4,934,094) discloses a grass sod reinforced with netting. Wengmann (U.S. Pat. No. 4,900,010) discloses an athletic field surface having therein flexible fibers and tree bark. Armond (U.S. Pat. No. 4,819,933) discloses a suitable surface for equestrian use using a sand mixture and polymeric fibers. Freed (U.S. Pat. No. 4,790,691) discloses composite mixtures of soil and fiber. McFarland (U.S. Pat. No. 4,786,550) discloses a lightweight seed mat formed with melt blown nonwovens. Shannon (U.S. Pat. No. 4,777,763) discloses plant growing medium having fibers. Rogers (U.S. Pat. No. 4,720, 935) discloses a growing medium having fibers. Thelen (U.S. Pat. No. 4,564,310) discloses a resilient playing field composition for play field sports fields. Decker (U.S. Pat. No. 4,336,668) discloses a novel method of growing groundcover sods reinforced with synthetic netting. Muldner (U.S. Pat. No. 4,190,981) discloses a complex lightweight seed mat using complex expensive equipment. Airhart in HortScience 18(1), 89-91, 1983 discloses groundcover and flower sods reinforced with synthetic netting.
In general, reinforced sod mats suffer from some important commercial drawbacks. With netting reinforcements, if the openings are large, harvest is usually delayed, while if the netting openings are small, the roots of the plants can be girdled. Neither leads to sod mats with both optimum sod mat production and growing characteristics. If the netting openings are large, the netting can also be troublesome to completely cover with planting medium. In addition, known reinforced sod mats do not have early planting medium stability to rains to prevent erosion during planting and early germination along with good long term resistance to surface soil erosion in particularly aggressive applications. Sod mats with both good short term and long term resistance to erosion which are also quick and easy to propagate are especially needed. Narrow accent strips for borders of ornamental plants are particularly difficult to propagate with good handling characteristics because many desirable accent or border plant strip sods have lower than desired root strength and/or root density. The consequences of this are plant sod strips have to tender edges and/or extended propagation times. Many sod mats known in the art use higher than required synthetic resins which add unnecessary costs to the sod mats.
In view of the above background, there still exists a need for sod mats which have a tough, stable surface layer combined with a 3 dimensional reinforcement structure which uses a minimum of synthetic resin and which can be quickly and easily propagated. There still exists a need for sod mats with improved stability to early, heavy rains, improved stability during very early harvesting, and improved planting medium binding for plants with less than optimum rooting structure. There still is a need for sod mats with both good short term and long term resistance to erosion which are also quick and easy to propagate for use in highway embankments and culverts. There still is a need for sod mats with the advantages of improved softness for foot paths and playing fields combined with improved long term soil stabilization performance for areas of high erosion potential and improved resistance to soil compaction. There still is a need for impact absorbing sod mats which improve the efficiency and effectiveness of fiber reinforcement and soft impact absorbing elastomers. There still is a need to develop improved accent border sods. There still is a need to minimize the consumption of synthetic resin in these stabilized sod mats. There still is a need to develop a manufacturing process for these sod mats with good production characteristics. Examples of good production characteristics are improved resistance to erosion from heavy rains, reduced propagation times along with reduced sensitivity to root binding, and improved sod mat handling characteristics. There still is a need for sod mats which can be harvested in very large rolls, easily transported, and rapidly installed on playing fields or sites requiring soil stabilization which have the above advantages.
New sod mats of this invention have a tough, stable surface layer combined with a 3 dimensional reinforcement structure which uses a minimum of synthetic resin and which can be quickly and easily propagated. New sod mats of this invention have a unique combination of reinforced layer of planting medium and sod reinforcements which have improved stability to early, heavy rains, improved stability during very early harvesting, and improved planting medium binding for plants with less than optimum root strength and density. New sod mats of this invention have both improved short term and long term resistance to erosion which are also quick and easy to propagate for use in highway embankments and culverts. New sod mats of this invention have advantages of improved softness for foot paths and playing fields combined with improved long term sod stabilization performance for areas of high erosion potential and improved resistance to soil compaction. Sod mats of this invention form improved accent and border plant sod mats. Impact absorbing sod mats with improved efficiency and effectiveness of fiber reinforcement and impact absorbing soft synthetic resin particles are developed in this invention. Sod mats of this invention minimize the consumption of synthetic resin in stabilized sod mats. A manufacturing process is developed for these sod mats with good production characteristics. Examples of good production characteristics are resistance to erosion from heavy rains, reduced propagation times along with reduced sensitivity to root binding, and improved sod mat handling characteristics. New sod mats are developed which can be harvested in very large rolls, easily transported, and rapidly installed on playing fields or sites requiring soil stabilization which have the above advantages.
Other objects and advantages of the current invention will become more apparent to those skilled in the art in view of the following description and examples.